[Elecraft] RE:balanced tuner

[Bob Tellefsen]

Hi David
I use the window line on a number of my antennas.
I twist the lines as a matter of course, the idea being
to somewhat equalize any unbalancing effects of
things in the nearby fields as the line passes by.
No scientific evidence that this is of real benefit, but
it makes me feel that I have at least tried to maintain
what balance there may be in the total antenna system.
73, Bob N6WG

----- Original Message ----- 
From: "David Cutter" <d.cutter at ntlworld.com>
To: "Elecraft Discussion List" <elecraft at mailman.qth.net>
Sent: Monday, August 18, 2008 10:08 AM
Subject: Re: [Elecraft] RE:balanced tuner


> For long horizontal lines near to the ground (<3ft, 1m, say) I've
read that
> some folks rotate the line between supports, supposedly to maintain
balance;
> what do you think about that?
>
> David
> G3UNA
>
>
> ----- Original Message ----- 
> From: "list1" <list1 at pituch.net>
> To: "Elecraft Discussion List" <elecraft at mailman.qth.net>
> Sent: Monday, August 18, 2008 4:29 PM
> Subject: [Elecraft] RE:balanced tuner
>
>
> > Hi David and all,
> >
> > I have done a lot of EZNEC dipole simulations and have come to the
> > conclusion that the loss in 100 feet of coax off of resonance is
about 12
> > dB
> > per 100'.  Whether you use RG-8x or LMR400 doesn't make too much
dfference
> > concerning losses off of resonance where your SWR with 50 ohm
transmission
> > line can be greater than 200:1.
> >
<http://www.pituch.net/Steve%27s%20Page/Radio/Antenna4/Antenna4.htm>
> > Because of this if I use 450 Ohm ladder line to a 1:1 baun, I try
to keep
> > the length of coax going into the house less than 15 feet. For
your 50
> > feet
> > of coax run you should never have a loss greater than about 1 S
unit (6
> > dB).
> >
> > When I went to 100 percent ladder line including inside the
residence,
> > when
> > I built my balanced tuner, I used two 1/4-20 stainless steel bolts
to feed
> > the signal through the exterior wood wall. I have "U" solder lugs
on the
> > two
> > wires at the end of the 450 Ohm line, and I use two wing nuts to
connect
> > the
> > ladder line to the house connection.  When I am finished operating
I go
> > outside at spend 5 seconds loosening the wing nuts and the ladder
line is
> > no
> > longer connected to the residence.  If I wanted further protction,
I guess
> > I
> > could drive a ground rod 15 feet away from the residence and wing
nut the
> > end of the ladder line to it when I am not operating.
> >
> > I don't believe you can keep your antenna connected to your
equipment and
> > ever be completely protected from lightning strikes (and that
includes
> > coax).  The air gaps don't work.  For coax the gas surge traps may
work to
> > a
> > degree, but I would much rather disconnect the transmission line
than
> > depend
> > on one of these devices.
> >
> > If you want so-called protection for 450 Ohm line why not use 2
Alpha
> > Delta
> > coax surge traps - one for each wire of the 450 Ohm line?
> >
> > The thing about keeping the 450 Ohm line away from metal is
overdone a
> > bit.
> > I find keeping it away from metal about 2 or 3 inches is fine.
> >
> > Regards,
> > Steve, W2MY
> >
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